Terence Blacker: Happy your online life is an open book?

As if we were caught up in some science fiction B-movie, a war is being fought over the control of our souls. As yet,the conflict is little more than a few light skirmishes – most of us are hardly aware it is happening – but, in the view of many, some mighty battles lie ahead in our cybernetic future.

Perhaps it is pushing it slightly to conflate the computer at which I am sitting with my soul, but not by much. My identity, opinions, political and personal affiliations, preferences, interests, buying habits and guilty secrets are all on a hard drive somewhere and are machine-readable. At the end of every day, I leave a "digital trail" behind me, rendering me vulnerable to the internet's danger strangers.

The wildest cowboys of cyberspace have been much in the news recently. There is Julian Assange whose copious leaks have posed such a threat to global peace and security. At a scruffier level, there is LulzSec, a small but effective group of computer hackers who have temporarily disabled the websites of the powerful, including the CIA and the UK's Serious Organised Crime Agency.

The breathless demonising of these activities suits both the hunters and the hunted. The police and press like to portray hackers as socially dysfunctional obsessives. These people are said to be psychopathic, weird, often on drugs. They pose a threat to all that is dear to modern society – Facebook pages, PayPal accounts.

The subversives glory in the panic they create. Their messages are couched in the language of war, and frequently lapse into swaggering Hollywood bad-guy prose. "You find it funny to watch havoc unfold, and we find it funny to cause it," LulzSec posted this weekend. "We release personal data so that equally evil people can entertain us with what they do with it."

Are you frightened yet? Worse is to come, and this time from within the business establishment. The fact is, our identities have already been hacked. Every time Google is used, or a website visited, or a purchase made, or a message sent, personal information is being logged, stored, and used.

In a new book The Filter Bubble: What the Internet Is Hiding from You, Eli Pariser has some alarming stories to tell. When two friends googled "BP" during the recent oil spill, one received investment advice, the other news of the spill. The computer knew the kind of thing which would interest them.

The same filtering and grading process, creepily known as "personalisation" or the "You Loop", happens with Facebook, says Pariser. Computers are presenting us with a cybernetic version of ourselves, reflecting back what it sees as our preferences and biases. As Bryan Appleyard has written, "Inside our bubbles and loops, we are watched and examined like lab rats with credit cards."

Set against this subtle and largely covert activity, a bit of conventional hacking suddenly seems insignificant. Personalisation, if it continues unchecked, means that news and opinions which do not accord with our own are being steered away from us, deepening the groove of prejudice every time we go online. The internet, with its illusion of opening up the world, is doing precisely the opposite. The polarising effect, the ironing out of conversation and disagreement, will shape our political future.

Which is the more scary, LulzSec or Google? In the end, the old-fashioned medium of language gives it away. The words of the hackers, while sometimes enraging, are those of an alienated, angry generation raging against what it sees as a corrupt, money-led world. Their corporate enemies communicate as if computers have already eaten their souls – and they are eager for ours to meet the same fate.